This revised application contains a research proposal to address two clearly defined and related problems: 1. The denaturation of single peptide chain proteins by hydrostatic pressure at temperatures below 0 degrees C, a possibility that depends on the decrease of the melting point of water to -20 degrees C at 2 kbar. 2. The effects of hydrostatic pressure upon myosin, actin and their mixed aggregates, at various temperatures. From these observations we shall derive the respective thermodynamic parameters for the transitions of peptide chains from globular to unfolded states, and those that correspond to states of actin and myosin aggregates believed to be of importance in motility. The results will be interpreted according to a recent theory of the author which relates the thermodynamic parameters to the differences in the average bond strengths of the reactants and products, and derives from these the characteristic pressure-temperature-volume relations of the system.